Lesson 11: The Periodic Table

In the previous lesson, we learned about the construction and composition of atoms, so in this lesson, we will learn how to read the periodic table of elements which is a Chemist's most important tool. This table, depending on how detailed it is, gives readily used information needed for calculations in chemistry.

Due to the complexity of the table, I won't draw one, but rather provide you with links to various tables. The former link leads to a basic table coupled with large amounts of additional. The latter link offers a very detailed table which would be more useful in more complex chemistry.

1. http://en.wikipedia.org/wiki/Periodic_table
2. http://www.dayah.com/periodic/

In this table, each element is represented by an abbreviation of one, two, or three letters. Some abbreviations correlate with the name of the element, such a C for carbon, but some represent Latin elemental names such as pb for lead.

Typically above each abbreviation is some whole number. This is called the atomic number and represents the number of protons in the nucleus of the atom. This number also represents the number of electrons in the atom if it the atom has an overall charge of zero.

The number below the abbreviation which is a number with some decimal is the average atomic weight of the atom. This number is the mass of the different isotopes for the element averaged together in terms of their abundances. Recall that from our last lesson, we established that one element is capable of having atoms of different masses because the atoms can have different amounts of neutrons. This number is used when the number of mols of atoms is being converted to mass. We will cover this more in detail later.

This table expresses many more traits of the elements being represented and we will cover these as we progress.

If you find this interesting, feel free to try to memorize the elements and associate them with their abbreviations. In chemistry the atomic abbreviations come up frequently so memorization would speed things up down the road. Otherwise, for occasional, casual chemistry, a periodic table can be referred to for abbreviations and elements.